1. Technical Field
The inventive arrangements relate generally to methods and apparatus providing advanced operating features for audio only, video only and both video and audio programs recorded on disc media, for example recordable digital video discs, hard drives and magneto optical discs.
2. Description of the Related Art
Various devices have been developed to enable consumers to record video and/or audio programs for later presentation. Such devices include tape recorders, video cassette recorders, recordable compact discs, and most recently, recordable digital video discs (DVD). Hard drives and magneto optical discs have also been used.
A DVD that can be recorded on only once, and thereafter is essentially a DVD read only memory, is referred to by the acronym DVD-R. The acronym DVD-R is also used generally to refer to the write-once, or record-once, technology. Several formats are available for DVD's to be recorded on, erased and re-recorded; that is, overwritten or rewritten. These are referred to by the acronyms DVD-RAM, DVD-RW and DVD+RW. As of this time no uniform industry standard has been adopted. The acronyms DVD-RAM, DVD-RW and DVD+RW are also used generally to refer to the respective rewritable technologies. Reference herein to rewritable DVD technology, devices and methods is generally intended to encompass all of the standards which are now being used, as well as those which may be developed in the future.
In many cases, the program presentations are recorded in the viewer's absence for presentation at a later, more convenient time. This is referred to as time shifting the program. At other times, the viewer may be called away while he is watching a program that is not being recorded. If the viewer owns a conventional video cassette recorder, the viewer may begin recording the program during the interruption. The viewer, however, must wait until the program is completed to watch the remainder of the program in a proper time sequence. A further complication is that the time to complete the recording can be excessive depending on the length of the broadcast. This can result in the viewer ignoring the interruption or missing significant portions of the program.
To overcome this problem, a DVD video recorder can incorporate a pause feature. When activated, this setting, similar to other conventional video recording machines, allows the viewer to record incoming video. Significantly, however, when the pause resume feature is activated, the DVD video recorder jumps back to that portion of the program where the pause was initiated to commence playback yet the recorder continues to record incoming video. As a result, a viewer, if interrupted for any number of reasons, can watch a program in its entirety without having to wait for the original broadcast to end.
Although it may appear to be simultaneous, the DVD recorder cannot read and write data at the same time. Thus, to achieve seamless playback, the DVD recorder must alternate between recording data on the disc and reading this data. The time allotted for either reading or writing data is determined, at least in part, by the limited size of the DVD recorder's data buffers. As a consequence, the recorder must constantly switch between reading and writing to avoid buffer overflow or underflow. The DVD recorder, however, cannot read or write data during these transitions. Therefore, this process of alternating between reading and writing data causes a significant decrease in the combined average bit rate associated with the reading and writing process. This presents a significant problem in that a relatively high average bit rate for reading and writing must be maintained in order to provide seamless playback.